Recovering from weasel attack

We had a small flock of two chickens and three ducks. Night before last a weasel got in and killed three, so now we are down to one of each. Our sweet duck has a neck strain, and both seem depressed. We're all pretty sad about it.

I am wondering what we can do to help her neck heal, and am concerned about their loneliness moving forward. I know chickens can be harsh with pecking order, so its not necesarily easy to introduce adult birds. Are ducks generally accepting of new birds? They are almost a year old.